Name:
Physical Science 7
Period:
Date:
COVALENT BONDS
1. Why do atoms form bonds with other atoms?
To achieve a stable valence shell
2. How can the number of valence electrons be determined just by looking at the periodic table?
Group 1 elements have 1 valence electron. Group 2 elements have 2 valence electrons. On the other side of the
transition metals, Group 13 elements have 3, Group 14 have 4, and so on.
3. What type of bond is formed when atoms share electrons?
Covalent
4. A group of atoms connected by covalent bonds is called what?
A molecule
5. Why are molecules neutral?
The atoms that make up molecules are neutral
6. What type of bond is formed when atoms share electrons unequally?
Polar bonds
7. Are all molecules with polar bonds considered polar molecules?
No, nonpolar molecules can contain polar bonds
8. How do polar molecules behave with each other?
The partially positive end of a polar molecules is attracted to the partially negative ends of other polar
molecules.
9. What has a higher boiling point: a polar molecule or a nonpolar molecule? Explain.
Polar molecules because it takes more energy to separate the molecules from one another.
10. What has a higher melting point: a polar molecule or a nonpolar molecule? Explain.
Polar molecules because it takes more energy to separate the molecules from one another.
11. How many electrons are shared in a single bond? A double bond? A triple bond?
Single bonds have two shared electrons. Double bonds have four. Triple bonds have six.
12. What types of elements typically form covalent bonds with each other?
Nonmetals and other nonmetals.
13. Draw a covalent bond between two nitrogen molecules. Include only valence electrons.
N
N
Name:
Physical Science 7
Period:
Date:
IONIC COMPOUNDS
1. An atom that gains an electron becomes what type of particle?
Negative Ion
2. An atom that loses an electron becomes what type of particle?
Positive ion
3. What type of element usually loses and electron? What type of element usually gains an electron?
Metals usually lose electrons. Nonmetals usually take electrons.
4. Why do positive ions and negative ions stick together?
Opposite charges attract.
5. A substance made of positive and negative ions bonded together is called what?
An ionic compound
6. An ionic compound usually has what type of structure?
A crystal structure
7. Why are ionic compounds neutral?
The charges of the positive ions balance out the charges of the negative ions.
8. What has a higher boiling point: an ionic compound or a molecular compound?
Ionic compounds.
9. What has a higher melting point: an ionic compound or a molecular compound?
Ionic compounds
10. What is a better conductor of electricity: an ionic compound or a molecular compound?
Ionic compounds
11. What bond is stronger: an ionic bond or a covalent bond?
Ionic bonds
12. Draw an ionic bond between an atom of lithium and an atom of fluorine. Include only valence electrons.
Li
F